Mammograms and the COVID-19 Vaccine

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Published on April 12, 2021

Mammograms and the COVID-19 Vaccine

Both Are Important – Don’t Delay Either

Illustration of masked women with pink ribbons on their bras under a caption reading "Cancer is not quarantined, check your breasts"If you follow women’s health news, you may have heard about the connection between the COVID-19 vaccine and false-positive mammograms.

Doctors have noticed that the Pfizer and Moderna COVID-19 vaccines can cause swollen lymph nodes under the arm in which the shot was given. These benign lymph node enlargements will show up on a mammogram, which may cause unnecessary worry. For this reason, some health care providers suggest that women either get their mammograms before the vaccine, or postpone their mammograms until four to six weeks after receiving the vaccine—enough time for the lymph nodes to go back to their normal size.

However, with more data and experience, PIH Health and many other large healthcare providers are no longer advocating any delay in screening mammography. We recommend that screening mammograms continue as scheduled—women’s breast health is too important.

“Reactive or swollen lymph nodes in the area after any vaccine are to be expected,” explains James Kuo MD, radiologist at PIH Health. “Lymph nodes are part of the body’s natural immune system, and swelling is a sign that the body is responding to the vaccine and building up defenses against COVID-19.”

In the vast majority of cases, with proper vaccination information, PIH Health radiologists can correctly attribute the swollen lymph nodes to the vaccination without further workup. “We believe this approach will prevent delays in both screening mammography and COVID-19 vaccination, dispel confusion, and provide patients with the best care possible,” says Dr. Kuo.

Bottom line: Don’t delay your mammogram on account of potential swollen lymph nodes and don’t delay vaccination either—both are important to your health. PIH Health radiologists are aware of the connection and factor any vaccination timing into their interpretation of results.

To schedule a mammogram visit

The information in Healthy Living Online is for educational purposes only.  It is not intended nor implied to be a substitute for professional medical advice.  The reader should always consult his or her healthcare provider to determine the appropriateness of the information for their own situation, or if they have any questions regarding a medical condition or treatment plan.